ACCUMULO-3089: Create volume chooser from table properties

Oh, I see. Yeah, I agree. The RandomVolumeChooser shouldn't change much. The preferredVolumes stuff should be rolled into the StaticVolumeChooser, since the static case is just a special case (only one preference). (And the StaticVolumeChooser should probably be renamed, and moved to examples, since it depends on custom user properties.)